Download Android Jelly Bean 4.2.2 stock firmware for Ainol Novo 7 Rainbow II tablet from here or from here. Download another Ainol firmware from here.
Archive name: Rainbow II
Archive file size: 744 MB
Firmware: Android Jelly Bean 4.2.2 stock firmware
Image file: a20_wing-novo707_2.0_1.1_v2_1009_20131009_152139.img
Model: Ainol Novo 7 Rainbow II tablet
Platform: Allwinner A20
Style: Numy_3G_AW1
FW version: v2.0 / 20131009
Pixels: 800 x 480
Company: softwinners / wing_novo707